I want to take input from external peripherals to PIC micro-controller(PIC18F66K22) through buffer IC(74HC541). My problem is o/p of buffer source current is +/-35mA and i/p of PIC18F66K22 PORTF pin is 2mA. And another case input clamp current of PIC18F66K22 is +/-20mA. We may directly interface these two IC's? And in what way input clamp current and sink current related or differs?

  • \$\begingroup\$ Are you planning to let one of these drive a pin high while the other is driving it low at the same time? \$\endgroup\$
    – PlasmaHH
    Jul 1 '16 at 12:12
  • \$\begingroup\$ No. Buffer was an output and PIC was an input. Buffer want to drive PIC \$\endgroup\$
    – Prakash
    Jul 1 '16 at 12:39

The buffer output current is the amount it can provide into a load and still maintain the \$V_{OH}\$ and \$V_{OL}\$ specifications.

The amount of current it will actually drive is dependent on the load, in your case a PIC input. (Make sure it is an input and not an output or you will get bus contention).

The input clamp current is the maximum that the PIC can handle if the current were injected (for instance if the voltage on the pin exceeded the supply).

So you can use the buffer and the PIC together without any issues.


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